Correlation of exercise capacity with high-sensitive C-reactive protein in patients with stable coronary artery disease

BACKGROUND: There is growing evidence for the association between physical activity and systemic inflammatory markers in healthy individuals and populations with a low prevalence of coronary artery disease (CAD). However, the association between fitness and CRP in patients with stable CAD treated with medications known to influence the inflammatory response, such as statins and aspirin, is not well known. METHODS: We prospectively enrolled 209 patients with angiographically documented CAD (161 men; age 63 +/- 10 years; 1-/2-/3-vessel disease in 42%, 34%, and 24% of patients, respectively; left ventricular ejection fraction 60% +/- 13%). Fitness level was assessed by maximal exercise testing. CRP was measured in all patients using high-sensitivity immunoassay. RESULTS: Fitness level was inversely correlated with natural log-transformed CRP level (r = -0.28, P < .001). After multivariate linear regression adjustment for age, sex, body mass index, waist circumference, smoking status, educational level, diabetes, hypertension, modality of exercise testing, exercise-induced ischemia, extent of CAD, medication use, leukocyte count, hemoglobin, renal function, glucose level, and cholesterol level, exercise capacity remained inversely correlated with CRP level (beta = -.226, P = .001). Other covariates associated with CRP remaining in the final model were leukocyte count (beta = .348), pack-years of smoking (beta = .185), diabetes status (beta = -.201), hemoglobin concentration (beta = -.187), and high-density lipoprotein cholesterol level (beta = -.149). CONCLUSIONS: These results indicate that exercise capacity is inversely correlated with CRP level in patients with known stable CAD irrespective of extent of CAD and standard medication for secondary prevention.